A machine, such as, for example, a continuous-flow machine, with a shaft and an oil-lubricated bearing can be provided with a blocking gas seal in order to prevent oil from leaking from the bearing. The blocking gas seal can have a blocking chamber between a rotating shaft wall which extends radially and the stationary bearing housing. When the machine is operating, when the shaft rotates and a blocking fluid is applied to the blocking gas seal, the blocking fluid in the blocking chamber is set in rotation via friction against the shaft wall. Owing to the action of the centrifugal force, a drop in pressure forms radially inward in the rotating blocking fluid, as a result of which the pressure at the bearing housing is disadvantageously low so that the oil can leak from the bearing housing.
The leaking of the oil is particularly critical when it occurs at the turbine outlet of a gas turbine because the oil can here come into contact with hot parts of the gas turbine. The oil can carbonize or burn as a result of the contact and consequently endanger the safe operation of the machine. The problem is usually solved by the blocking fluid being applied at high pressure to the blocking gas seal, but this is disadvantageous for the efficiency of the gas turbine.
A bearing arrangement is moreover known from US 2012/201661 A1, in which an elevated pressure can be generated in an intermediate space which is shielded in each case via a labyrinth seal, on the one hand with respect to a hydraulic bearing and, on the other hand, with respect to a space at atmospheric pressure. The elevated pressure is generated with the aid of a fluid line which opens into the intermediate space and by means of which a corresponding fluid can be conveyed. The intermediate space can thus be further divided by a shield in order to establish the partial space with the localized elevated pressure as close to the end of the labyrinth seal as possible. It is, however, hereby disadvantageous that there is a need for an elevated pressure to generate a reliable seal.